Dashpot for time lag relays



Jan. 2, 1934. F. WOLFF DASHPOT FOR TIME LAG RELAYS Filed Nov. 25, 1930 2 Sheets-Sheet l F. WOLFF Jan. 2, 1934'.

DASHPOT FOR TIME LAG RELAYS Filed NOV. 25. 1950 2 Sheets-Sheet 2 Patented Jan. 2, 1934 UNITED STATES PATENT OFFICE Application November 25, 1930, Serial No. 498,020, and in Germany November 25, 1929 8 Claims. (01. 1887-94) The present invention relates to a time lag relay working with a container to be wholly or partly freed from the air it contains and into which the air can be made to gradually enter again.

Devices of this kind are already known which are working with a closed, elastic hollow body, the latter being provided with inletand outlet valves for the air and capable of being compressed by means of a pressing means when actuating the relay. In one of the known arrangements of this kind the disposition is such, that, on pressing down a push button the air is forced out of an india-rubber ball being provided with an opening fitted with a valve; Upon releasing the push button, the action of a spring arranged on said button causes it to return to its original position independent of the india rubber ball, whilst the latter, however, only gradually expands again to its original size in a measure as the air freshly penetrates into the ball through said valve. In view of the fact, however, that the external pressure does not exceed the pressure prevailing in the interior of the compressed india-rubber ball, this ball will not possess any tendency, or at least to a very slight extent only, to dilate again to its original dimensions, which phenomenon will be exhibited by any india-rubber playing ball which has been pierced at any one point. It is, therefore, obvieus, that an arrangement of this kind cannot work at all in a practical manner, unless it has been provided with special springs, in order to cause the ball to adopt its original shape again.

In a second known arrangement of this kind separate inletand outlet valves'for separate openings of the india-rubber ball, also made use of in this case, have been provided. In this arrangement, too, the push button is disposed independently of the india-rubber ball and returns into its original position owing to the action of a special spring. The re-dilation of the india-rubber ball is also supposed in this case to take place automatically, but for the reasons mentioned above also in this case this will not be possible either at all or, at any rate,

not under development of force, and the redilation of the india-rubber ball and with it the opening of the contacts provided for that purpose will generally take place only under the action of a spring connected with the indie.- rubber ball and the contact.

In no case would it be possible to actuate by means of such arrangements a sliding or knife contact such as required for power current specially shaped elastic hollow body being made 05 use of is provided with a hollow cylindrical attachment or with stiifenings or reinforcements of its walls in such a manner, that its tendency of re-dilation after having been compressed, will be assisted and enhanced thereby, a very considerable force being developed at the same time, which force renders it possible to surely effect the opening of the previously closed contact in a desired manner, even ifsliding or knife contacts for power current switches requiring a greater amount of power are used The force developed by the re-dilation or re-expansion of the reinforced hollow body may evidently also be utilized for the purpose of effecting other work.

The re-dilation or re-expansion of the compressed hollow body essentially takes place in this instance as a result of its special shape or of the reinforcing stiffenings or of both, and the re-entrance of the air into the hollow body takes place in correspondence with its progressive re-dilation or re-expansion.

The most suitable shape of the hollow body for a certain power eiiect of a time lag relay differs according to the effect of lift and the height of lift desired. An essential feature in this 50 connection is the provision of a hollow-cylindrical or neck-like attachment for the hollow body, said neck-like attachment being suitably formed above a tapering part of the hollow body and'being preferably employed as pressure point.

The stiffenings or reinforcements of the elastic hollow body are preferably wholly or partly curved or arched. Care, however, should be taken that the force exercised by these stiffenings on releasing the compressed hollow body does not become so strong, that the hollow body will assume its original shape rapidly prior to the re-entrance of the air, in opposition to the atmospheric pressure acting upon its external surface. The arrangement should rather be such, that the re-dilation or re-expansion of the elastic hollow body will correspond to the gradual,

entrance of the air, thus requiring a certain period which may be regulated if required, and as it may be desirous for the purpose of actuating the shape of bellows and the like.

1 arched shape.

the time lag relay or the like. The present invention will be applicable everywhere cut-out and change-over effects with certain retardations, particularly for electrical purposes, are to be effected, and it will render it possible to renounce the insertion of clock-works, electro-magnets or the like, as, for instance, for the lighting of staircases, lifts, for magnetic apparatus, reversible couplings in machines or the like, and furthermore it ensures a considerable simplification of the construction of appliances serving these purposes.

In the accompanying drawings automatic elec-- tric time lag switches in conjunction with a time lag relay in accordance with the present invention have been illustrated as examples of execution.

Fig. 1 represents a time switch of this kind partly in section, in an off position with the circuit cut out. Fig. 2 illustrates the same device in working position shortly after being cut in. Fig. 3 represents a somewhat modified form of construction of the time switch shown in Fig. 1 in an off position, in longitudinal section. Fig. 4 shows a horizontal section along the line of section shown in Fig. 3. Fig. 5 shows another constructional form of the hollow body made use of, in longitudinal section, and Fig. 6 represents a cross sectional view of the body shown in Fig. 5, along the line of section indicated in the latter.

Within a casing 1 a hollow body 2 made of an elastic material impervious to air, as for instance: Soft rubber, impregnated fibre material, gold beaters skin, impregnated artificial or natural leather, or any other animal, vegetal or artificial suitable substances, is arranged, said elastic hollow body 2 being connected with a valve casing 4. The interior walls of the casing 1, which is covered by the cap 3, are of such a shape that the hollow body 2 when filled with air may snuggle thereto.

Below the cap 3 a pedestal 7 with a pivot 8 for a switch-lever 9 and a contact spring 12 with connecting screw 13 have been arranged on the top of easing 1. The valve-casing 4 has been provided with two stops 10 and 11 between which the switch-lever 9 is made to operate. A spring 14 for the lever 9 ensures sudden interruption in cutting out or changing over.

The shape of the hollow body 2 may vary. It may for instance be of spherical, oval, cylindrical shape, or it may also be formed of a combination of such various shapes, or it may have The essential feature of construction of the hollow body 2 always consists in that it is provided with a necklike attachment and that its walls possess stiffenings or reinforcements in such a manner, that its re-dilation or re-expansion after having been stifienings or reinforcements have not been rendered visible in Figs. 1 and 2. In the example of performance of Figs. 3 and 4, however, stiffening or reinforcing ribs 15 are to be seen as arranged on the inner wall of the hollow body 2,

said ribs 15 running from the bottom of the body 2 in an upwards direction and terminating only at the neck-like attachment 1''! of the hollow body 2. In the example shown in Figs. 5 and 6 the stiffening or reinforcing ribs 16 are of an The ribs 15 and 16 preferably consist of the same elastic material as the hollow body 2 proper, i. e. of india rubber or the like.

Owing to these stiffenings or reinforcements it is attained that the upper, cone-shaped part of the hollow body 2 always will have the tendency of assuming its original position whilst simultaneously developing a certain power effect when it has been depressed before. It will, however, be necessary to take care, that the extent of the force accumulated as a result of the compression of the elastic body 2 will be adapted to the requirements of the case. The special construction of the hollow body 2 and of the stiffenings or reinforcements provided thereon further ensures that particularly the last part of the redilation or re-expansion movement of the hollow body takes place in the form of a short, jerk-like stretching, whereby a considerable force is developed.

The construction of theinlet and outlet valves may be gathered from Fig. 3. The essential difference between the arrangement shown in this figure and that shown in Figs. 1 and 2 merely consists in that instead of a bar 6 extending in a downward direction from the valve casing 4 and provided for the purpose of actuating the air outlet valve, a pin 24 extending in an upward direction and projecting from the rod-like valve casing 4 has been arranged, said pin carrying a valve spindle 23, which in its turn is carrying a valve body 22. The seat 21 of the air outlet valve is screwed into the rod-like casing 4, through which the canal 20 is made to pass. The valve 21, 22 is ordinarily kept closed by a spring 25.

The air inlet valve is also arranged within the rod-like casing 4, and essentially consists of a washer 26 permeable to air, a counter nut 27 is placed above said washer. Said nut 27 may be tightened or loosened, as required, from the outside. The compression or release of the permeable washer 26 effected thereby will have the effect that the air is made to enter more slowly or more rapidly through this valve body into the hollow body 2, according to requirements.

The connection between the neck-like part 17 of the hollow body 2 and the rod-like valve casing 4 in the example of performance shown in Fig. 3 is established by means of the sleeve 18 being screwed or otherwise fastened to the casing 4 and fitting the upper end of the hollow body 2.

The upper end of the hollow body 2 and the rod-like valve casing 4 are guided at the middle opening of the upper edge of the casing 1 and within the bore of the cap 3, whereby a straightlined motion of the part 4 is ensured. This guiding action may also be effected at other points according to the shape of the hollow body.

The operation of the shown device is as follows: By exercising pressure upon the cap 5 (Figs. 1 and 2) the rod-like valve casing 4 is pressed downward, simultaneously compressing the hollow body 2. As soon as the rod 6 of the outlet valve situated in the valve casing 4 during this motion is pushed against the bottom of hollow body 2, the outlet valve will be opened and the air will flow out with great velocity. In the example of performance in accordance with Fig. 3 the opening of the outlet valve 21, 22 is efiected immediately upon pressing the pin 24. In any other direction the construction and operation of the valves are identical in both examples of execution. The hollow body 2 remains at first in the compressed state (Fig. 2) when, upon releasing the valve casing 4 the outlet valve closes again. Whilst pressing down the valve casing 4 the stop 10 has pressed the switch lever 9 down to ,such extent that it will engage the contact spring 12 thereby closing the circuit.

Owing to the entrance of air through the: inlet valve 26 disposed within the casing 4, the hollow body 2 gradually dilates or expands again accurately in accordance with the regulation of the supply of air, essentially under the action of the stiffenings or reinforcements 15 or 16 with which it has been provided. The valve casing 4 is taken along thereby, whereupon the stop 11 will abut against the switch lever 9 pushing it out from the contact spring 12 upon attaining a certain force of pressure, whereupon the said lever 9 snaps back into its open position under th action of the spring 14. i

The short, jerk-like stretching operation of the hollow body 2 at the end of its re-dilation or re-expansion movement will begin when a certain quantity of air in proportion to the interior space of the hollow body has entered again, without, however, equalling the quantity which the hollow body ordinarily may hold without excess pressure. The last part of the return movement of the hollow body to its original position is therefore effected under the action of its natural elasticity and of its stiffenings or reinforcements before the corresponding quantity of air will have re-entered, i. e. under formation of a certain partial vacuum in the interior of the hollow body, thereby causing a sudden power effect as it is of great importance for the rapid actuation of mechanical connections after the end of the retarding work of the relay, e. g. for the rapid opening of a sliding contact. If this power effect shall be used for the overcoming of mechanically greater effects, such as spring pressure, friction resistance of the apparatus and the like working in conjunction with the relay, the premature, positively automatic opening of the inlet and outlet valves offers the possibility of enhancing this effect.

According to the adjustment of the inlet valve 1 26 the work of cutting out may be rendered accurate to within seconds; where ordinary dimensions are used, this may require 2 seconds, but also 1 hour or even more, as desired, whilst with larger dimensions any other desired switching period may be attained.

If desired, the inlet valve may also be constructed such that it will be closed when compressing the hollow body, or that it closes auto matically, e. g. in dependance upon the opening of the outlet valve and that it opens again as soon as the external pressure upon the valve body has ceased, or that also the outlet valve after the beginning of the compressing movement or of the re-dilation movement will positively work with parts of the apparatus to be operated or also as an inlet valve; it is always essential, however, that the re-entrance of the air through this valve requires a predetermined shorter or longer period and that the rapidity of this process is limited in regard to time or desired power effect.

In cases where the attainment of higher power effects is required than the natural elastic force of the hollow body may furnish, as with pawls in machines and the like, a spiral spring or the like may be provided inside or outside of the hollow body 2, as an additional source of power.

It is also essential that the original cross section oi the hollow bodyupon compressing the latter, will not be changed in an undesirable manner, because otherwise a positive stretching to the original state would be rendered difficult or even made impossible.

By changing the diameter of the pressure surface and its formation or by arranging a longer or shorter way for the valve casing 4, it will be found possible to effect the discharge of air from the hollow body more or less rapidly just as it may be deemed suitable for the desired purpose.

By correspondingly constructing the casing 1 it is also possible, to limit the movements of the hollow body in such a manner as it may be considered suitable for its kind of operation. If desired, the hollow body may be provided with a plurality of pressure or valve casings, so that it may act in various directions and work at different times in these various directions. -It will also be possible to collect the air escaping from the hollow body in another hollow body or container and to allow sucha combination to work, together with a corresponding construction of the valves, in accordance with: the present invention. The power effect attained according to the kind of construction of the hollow body allows of being utilized in many different ways for switching purposes and the like, and a connection with any desired devices for the most varying purposes may be effected directly or indirectly by means of levers, eccenters, springs and the like. The fact, that packing by means of collars and pistons have been avoided, causes the relay to be particularly insensitive against temperature influences, so that even for very considerable differences in temperature no deviation of any importance from the working period once adjusted upon is noticed, nor will the accuracy of the operation in any way be impaired.

Instead of actuating the relays by hand, this may also be done mechanically, e. g. electromagnetically with the aid of a solenoid, or the like.

Having now particularly described and ascertained the nature of my said invention, I declare that what I claim is:

1. A time lag relay, particularly for electrical circuit switches and changing over purposes, having a closed elastic hollow body, air inlet and outlet valves arranged on said hollow body, and means for compressing said hollow body, said elastic hollow body having reinforcements thereon for enhancing the re-expansion force of said hollow body after having been compressed.

2. A time lag relay, particularly for electrical circuit switches and changing over purposes, having a closed elastic hollow body, air inlet and outlet valves arranged on said hollow body, and means for compressing said hollow body, said elastic hollow body having strengthening ribs enhancing the re-expansion force of said hollow body after having been compressed, said strengthening ribs being arranged on the interior walls of said hollow body and being formed archlike 3. A time lag relay, particularly for electrical circuit switches and changing over purposes, having a closed elastic hollow body, air inlet and outlet valves arranged on said hollow body, and means for compressing said hollow body, reinforcements on said hollow body for enhancing the re-expansion force of said hollow body after having been compressed, said reinforcements being formed of the same material as said hollow body proper.

4. A time lag relay, particularly for electrical circuit switches and changing over purposes, having a closed elastic hollow body, air inlet and outlet valves arranged on said hollow body, and means for compressing said hollow body, said elastic hollow body having strengthening ribs enhancing the I'B-GXPaHSiOH force of said hollow body after having been compressed, said strengthening ribs running in the direction of the pressure exerted during the compression of said hollow body.

5. A time lag relay, particularly for electrical circuit switches and changing over purposes, having a closed elastic hollow body, air inlet and outlet valves arranged on said hollow body, and means for compressing said hollow body, said elastic hollow body having reinforcements enhancing the re-expansion force of said hollow body after having been compressed, and means for transmitting the force exerted by said expanding hollow body to devices to be operated thereby.

6. A time lag relay particularly for electrical circuit-switches and changing-over purposes, comprising a closed hollow body, the walls of said hollow body consisting of elastic material, air inlet and outlet valves on said hollow body, and means for compressing said hollow body, said elastic hollow body having reinforcements thereon for enhancing the re-expansion force of said hollow body after having been compressed, one end of said elastic hollow body being cone-shaped.

7. A time lag relay particularly for electrical circuit-switches and changing-over purposes, comprising a closed hollow body, the walls of said hollow body consisting of elastic material, air inlet and outlet valves on said hollow body, and means for compressing said hollow body, said elastic hollow body having reinforcements thereon for enhancing the i e-expansion force of said hollow body after having been compressed, and said elastic hollow body having a. neck-like portion made hollow and cylindrical.

8. A time lag relay particularly for electrical circuit-switches and changing-over purposes, comprising a closed hollow body, the walls of said hollow body consisting of elastic material, air inlet and outlet valves on said hollow body, and means for compressing said hollow body, said elastic hollow body having reinforcements thereon for enhancing the re-expansion force of said hollow body after having been compressed, and said elastic hollow body having a necklike portion made hollow and cylindrical, one end of said elastic hollow body being coneshaped.

FRANZ WOLFF. 

